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Home »Python »Python Programs
Check Empty NumPy Array: In this tutorial, we will learn how to check whether a NumPy array is empty or not using different methods?By Pranit Sharma Last updated : May 26, 2023
Problem Statement
Given a NumPy array, we have to check whether it is an empty array or not.
Checking whether a NumPy array is empty or not
To check an empty NumPy array, there are multiple methods that you can use such as numpy.ndarray.size attribute, numpy.any() method, and numpy.size() method. Let's discuss all these methods with examples.
1) Using numpy.ndarray.size Attribute
The ndarray.size attribute returns the total number of elements in a NumPy array. If the given array is empty, it returns 0; the Number of elements, otherwise.
Syntax
ndarray.size
Example 1:
Consider the below Python program to check NumPy array is empty or not using ndarray.size attribute.
# Import NumPyimport numpy as np# Creating empty and non-empty arraysarr1 = np.array([])arr2 = np.array([10, 20, 30])# Printing original arraysprint("arr1:\n", arr1, "\n")print("arr2:\n", arr2, "\n")# Check whether array is empty or not# using ndarray.size attributeif arr1.size == 0: print("arr1 is an empty array")else: print("arr1 is not an empty array")if arr2.size == 0: print("arr2 is an empty array")else: print("arr2 is not an empty array")
Output
arr1: [] arr2: [10 20 30] arr1 is an empty arrayarr2 is not an empty array
2) Using numpy.any() Method
The numpy.any() method checks whether any array element along a given axis evaluates to True. If the given array is not empty it returns True; False, otherwise.
Syntax
numpy.any(a, axis=None, out=None, keepdims=<no value>, *, where=<no value>)
Example 2
Consider the below Python program to check NumPy array is empty or not using numpy.any() method.
# Import NumPyimport numpy as np# Creating empty and non-empty arraysarr1 = np.array([])arr2 = np.array([10, 20, 30])# Printing original arraysprint("arr1:\n", arr1, "\n")print("arr2:\n", arr2, "\n")# Check whether array is empty or not# using numpy.any() methodif np.any(arr1) == False: print("arr1 is an empty array")else: print("arr1 is not an empty array")if np.any(arr2) == False: print("arr2 is an empty array")else: print("arr2 is not an empty array")
Output
arr1: [] arr2: [10 20 30] arr1 is an empty arrayarr2 is not an empty array
3) Using numpy.size() Method
The numpy.size() method returns the total number of elements in an array along a given axis (optional). If the given array is empty, it returns 0; the Number of elements, otherwise.
Syntax
numpy.size(arr, axis=None)
Example 3
Consider the below Python program to check NumPy array is empty or not using numpy.size() method.
# Import NumPyimport numpy as np# Creating empty and non-empty arraysarr1 = np.array([])arr2 = np.array([10, 20, 30])# Printing original arraysprint("arr1:\n", arr1, "\n")print("arr2:\n", arr2, "\n")# Check whether array is empty or not# using numpy.size() methodif np.size(arr1) == 0: print("arr1 is an empty array")else: print("arr1 is not an empty array")if np.size(arr2) == 0: print("arr2 is an empty array")else: print("arr2 is not an empty array")
Output
arr1: [] arr2: [10 20 30] arr1 is an empty arrayarr2 is not an empty array
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